The health boom in recent years has been accompanied by growing interest in technologies in which tea and tea extracts are incorporated into architectural materials, filters and the like.
For instance, JP 2002-321205 A proposes a method for producing wooden boards having antibacterial activity, by incorporating used tea leaves in a wooden board producing process. With transport costs and other expenses in mind, however, procurement of used tea leaves requires finding a tea drink plant that is located in the vicinity of the wooden board factory. Assuming there is a tea drink plant in the neighborhood of the wooden board factory, it becomes then necessary to coordinate the producing schedule of both facilities, and to invest in equipment for sourcing a single type out of the tea drink residues.
JP 2001-348968 A proposes a method for producing interior architectural materials having the capability of adsorbing hazardous chemical substances, by incorporating tea leaves, or a component contained in tea leaves, into the interior architectural material. This method can conceivably be applied to the producing process of wooden boards, which becomes then a method for producing antibacterial or deodorizing wooden boards containing a green tea polyphenol, by adding the green tea polyphenol, as a component contained in tea leaves, to wood fibers, obtaining thereafter a wood mat by forming, and drying then the wood mat. However, large amounts water are wrung out during obtention of the wood mat through forming of a wood fiber slurry, and thus the green tea polyphenol is lost at the time of forming. Moreover, green tea polyphenols decompose readily on account of the drying temperature. Patent document 2 discloses no detailed tea leave addition amounts and no effective examples. When tea leaves are added thus in the addition amount of the used tea leaves disclosed in Patent document 1 in case of addition of tea leaves in place of a green tea polyphenol, the cost incurred in doing so is problematic, since the weight of the added tea-leaf dry product amounts to about 1 to 5 kg per 1-tatami size (about 1.65 square meters) of insulation board.
Thus, no conventional wooden board production methods are known that allow a green tea polyphenol to be incorporated efficiently and stably in wooden boards.